Hmm... as an avid user of dropbox, parallels and utorrent, I can safely say it wouldn't be those programs. I'm rather paranoid when operating on wifi and have always made sure I am not sharing anything if I don't intend to... anyways it looks like something is modifying your permissions. I am not sure about logmein though, but I am familiar with what it does.

one thing you could try to test this theory is by making a new account. try to replicate the problem through that account.

You could also try this method:

Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, highlight your drive, click on Repair Permissions, then move these files to the Desktop: